Copper-base alloy



Patented June 10, 1941 COPPER-BASE ALLOY Edward S. Bunn and Irving T. Bennett, Rome,

N. Y., assignors to Revere Copper and Brass Incorporated, Rome, N. Y., a corporation of Maryland No Drawing. Application September 16, 1939, \Serial No. 295,332

4 Claims.

Our invention, which relates to copper-base alloys, has among its objects the provision of a stable alloy of low melting point which may be compounded by ordinary metallurgical processes and readily fabricated into shapes by ordinary mill processes.

Heretofore it has been proposed to reduce the melting point of copper by additions of phosphorus. Such alloys however are extremely brittle, cannot be hot forged or hot extruded, and can be hot rolled only with difficulty.

The minimum melting point that can be obtained by additions of phosphorus to copper is about 707 C. occurring when about 8.2 5% phos-- phorus is added, any increase or decrease in this amount of phosphorus causing an increase in the melting point. Applicants however have found that by adding suitable amounts of both arsenic and phosphorus to copper a melting point can be obtained which is lowerthan that which can be obtained by adding phosphorus alone, and at the same time there can be produced an alloy that in respect to its ease of hot workability is comparable to that of copper.

The improved alloys being much less brittle when cold than the binary copper-phosphorus alloys are much less liable to fracture. Further, as distinguished from the binary copper-phosphorus alloys, the improved alloys are characterized by relatively great plasticity when hot, enabling them to be readily extruded, forged and rolled, while hot, by usual commercial mill operations. The binary alloys may be reduced by hot rolling, but only about without reheating, and only through a narrow range of about 50 to 70 C. The improved alloys however may be reduced by hot rolling about 75% through a wide range of about 200 C. without reheating. Applicants preferred alloys contain about 5.5 to 6% phosphorus and'2 to 4.5% arsenic, and have melting points ranging from about 655 to 685 C., which are well below the minimum melting point that can be obtained by the addition of phosphorus alone in any amount. At the same'time the alloys have'the further improved properties hereinbefore mentioned. An extremely satisfactory alloy according to the invention contains about 5.6% phosphorus and 4.2% arsenic, and has a melting point of about 660 C. The low melting point of these preferred alloys makes them useful for brazing material. 1

Neglecting melting points the improved physical properties of applicants alloys it has been found will exist with from 4.5 to 8.5% phosphorus and 0.5 to 5% arsenic, the melting point however in all cases being lower, and in most instances markedly lower, than that of the binary copper-phosphorus alloy having the same amount of phosphorus. Throughout ranges the alloy is believed to consist substantially of a eutectic mixture of phosphorus and a solid solution of copper and arsenic, as it has been found that up to about 8% arsenic is so1-' uble in copper, but only about 0.1% phosphorus.

The melting point of the improved alloy may be controlled by varying the amounts of phosphorus and arsenic added. For example, with 4.5% phosphorus, which causes a binary copperphosphorus alloy to have a melting point of about 900 C., the melting point of the improved alloy may be varied from about 880 0. down to about 670 C. by progressively increasing the amount of arsenic from 0.5 to 5%, while with 8.5% phosphorus, which causes a binary copper-phophorus alloy to have a melting point of about 715 C., may be varied from about 695 C. down to about 640 C. by the same progressive increase in the percentage amount of arsenic. 0.5% arsenic the melting point of the improved alloy may be varied from about 880 C. down to about 695 C. by progressively increasing the amount of phosphorus from 4.5 to 8.5%. while' with 5% arsenic may be varied from about 670 C. down to about 640 C. by the same progressive increase in the percentage amount of phosphorus. It will therefore be clear that by proper selection of the amounts of phosphorus and arsenic themelting point of the improved alloy may be made lower than that which can be obtained with any amount of phosphorus alone.

It will therefore be clear that as compared with binary copper-phosphorus alloys the alloy according to the invention is much less brittle, has a lower melting point, is much more plastic when hot, and is plastic through a wider range of temperature, and iurther that it may be hot forged and hot extruded, and may be worked with greater ease by hot rolling.

Within the scope of the invention the basic ternary alloy may contain small amounts of other metals or metalloids, say as impurities or deliberately added for modifying its characteristic ing point less than that of the binary copper phosphorus alloy of the same phosphorus content, are not destroyed, in which sense the alloy consists of arsenic and phosphorus, within the these Similarly, with ranges specified, with the balance substantially all copper.

We claim:

1. Alloys consisting of arsenic 0.5 to 5%, phosphorus 4.5 to 8.5%, balance substantially all copper.

2. Alloys consisting of arsenic 2 to 4.5%, Phosphorus 5.5 to 6%, balance substantially all copper.

3. Hot workable alloys having melting points not in excess of 700 C. consisting of arsenic and phosphorus with the balance substantially all copper, the amounts of arsenic and phosphorus being within the limits of 0.5 to 5% and 4.5 to 8.5%, respectively, of the total arsenic, phosphorus and copper contents of the alloys.

4. Hot workable alloys having melting points Within the limits of 655 to 685 C. consisting of arsenic and phosphorus with the balance substantially all copper, the amounts of arsenic and phosphorus being within the limits of 2 to 4.5% and 5.5 to 6%, respectively, of the total arsenic,

l0 phosphorus and copper contents of the alloys.

EDWARD S. BUNN. IRVING T. BENNETT. 

